The present invention is in a casting resin or a hardenable composition based on hardenable acrylic and methacrylic acid esters and finely divided inorganic fillers which contain a mixture of metallic acid esters and organic silicon compounds as adhesivizing agents. The casting resin is flowable at its pouring temperature.
It is known to mix inorganic fillers with casting resins based on hardenable acrylic and methacrylic acid esters, referred to also herein as unsaturated casting resins. Casting resins are also known which contain the inorganic fillers in percentages exceeding 50%, and in which these fillers are required to be particularly finely divided. In these last-named casting resins, the use of organic silanes as adhesivizers has also been described (cf. DE-OS 2 449 656, U.S. Pat. Nos. 4,221,697 and 4,251,576). These known casting resins containing finely divided fillers have higher densities than unfilled, unsaturated casting resins, and greater hardness and improved stiffness. Also, the inorganic fillers diminish the shrinkage of the resins as well as their temperature rise during hardening.
The high content of finely divided fillers which is finely distributed in the casting resins when organosilanes are used as adhesivizing or bonding agents, increases the bending strength and impact toughness of the moldings made from these resins. Moldings which are manufactured from these known, unsaturated casting resins include sanitary products, such as for example sinks or washbasins.
In the manufacture of these moldings, the unsaturated casting resin is to have a very low viscosity so that, when it is poured into the molds it will fill them out completely and to the correct degree. This requirement is not met by many unsaturated casting resins on account of their high content of fillers. Neither can this problem be solved by the addition of organosilicon compounds. Certain organosilicon compounds actually produce a further increase in viscosity.
The problem therefore existed of improving the known unsaturated casting resins based on acrylic acid esters and finely divided inorganic fillers and containing organosilicon compounds as adhesivizers such that they will have the viscosity that is necessary for their use, but one much lower than that of the unmodified casting resins. The new casting resins, however, are also to have the same good physical characteristics as the known unsaturated casting resins.